Étude comparative de la vitrectomie transconjonctivale sans suture à 25-gauges avec celle à 20-gauges

Design Parameters for a Small-Gauge Fragmatome

Purpose

Manufacturers of surgical instrumentation have increasingly sought to decrease the size of ophthalmic surgical instruments. We have used finite element modeling to model the stress and strain present in a fragmatome as a function of driving frequency and fragmatome dimensions.

Methods

Finite element calculations using the COMSOL Multiphysics system v3.5 were used to elucidate the influence of wall thickness, length, and excitation frequency on a titanium fragmatome tube with outer diameters of 20, 23, 25, and 27 gauge.

Results

By coupling structural mechanics, fluid mechanics, and acoustical physics, we were able to determine the eigenfrequencies (resonant frequencies) as well as parameters in which the von Mises stress in a fragmatome tube exceeds the yield strength, leading to destruction of the instrument.

Conclusion

Solid fragmatomes have far fewer possible failure modes than fragmatomes with a standard wall thickness. Eigenfrequency analysis and finite element calculations can be critical in predicting potentially catastrophic designs in modern surgical instruments.

Translational Relevance

Instruments developed for microsurgical applications cannot always simply be scaled down versions of conventional instruments. Such an approach can lead to potentially dangerous intraoperative failures, such as a fragmatome shattering inside the eye. Modern engineering techniques are increasingly necessary to investigate potential instrument failure mechanisms and to optimize device performance in a design in silico before in vivo testing.

Comparison of postoperative ciliary body changes associated with the use of 23-gauge and 20-gauge system for pars plana vitrectomy

Background

To compare the ciliary body changes associated with the use of 23-gauge (23G) and 20-gauge (20G) systems for pars plana vitrectomy.

Methods

A total of 60 patients (60 eyes) with idiopathic epiretinal membrane who were scheduled for surgical treatment were selected and randomly assigned to 20G group or 23G group. Time required for incision making, vitrectomy, and incision closure was compared between the two groups. Changes in ciliary body were evaluated by ultrasound microscopy (UBM). Anterior chamber inflammation was assessed with laser flare meter instrument.

Results

Incision-making time (4.5 ± 0.9 min) and incision-closure time (2.8 ± 0.7 min) in the 23G group were significantly shorter than those in the 20G group (10.1 ± 1.5 min and 11.3 ± 2.2 min, respectively). No significant intergroup difference was observed with respect to time required for vitrectomy (21.6 ± 3.3 min and 20.7 ± 3.2 min, respectively). Ciliary body thickness in the 23G group recovered back to preoperative levels after 4 weeks, as against 8 weeks in the 20G group. Postoperative ciliary body thickness in the 20G group was significantly higher than that in the 23G group (p < 0.05). The aqueous protein concentration in 23G group recovered back to preoperative levels after 2 weeks, as against 4 weeks in the 20G group. Postoperative aqueous protein concentration in the 20G group was significantly higher than that in the 23G group (p < 0.05).

Conclusions

The use of 23G system was associated with significantly milder injury to the ciliary body as compared to that associated with the use of 20G system.

Trial registration

The study was retrospectively registered on Chinese Clinical Trial Registry. The clinical study registration number was ChiCTR-INR-17011082. Date of registration: 2017-04-07.

Performance Comparison of High-Speed Dual-Pneumatic Vitrectomy Cutters during Simulated Vitrectomy with Balanced Salt Solution

PURPOSE

To measure flow rate of balanced salt solution and IOP during simulated vitrectomy using two sets of high-speed dual-pneumatic probes.

METHODS

A closed-model eye system measured IOP and flow rate of a balanced salt solution through infusion cannula. The Constellation Vision System was tested with two sets of high-speed dual-pneumatic probes (UltraVit 23-gauge and enhanced 25+-gauge 5000-cpm probes; UltraVit 23-gauge and enhanced 25+-gauge 7500-cpm probes; n = 6 each) under different vacuum levels and cut rates in three duty cycle modes.

RESULTS

In both probe sets, flow rates were dependent on cut rate with the biased open and biased closed duty cycles. Flow rates were highest with the biased open duty cycle, lower with the 50/50 duty cycle, and lowest with the biased closed duty cycle. IOP, as expected, was inversely associated with flow rate using both probe sets.

CONCLUSIONS

The 7500-cpm probes offer greater control and customization compared with 5000-cpm probes under certain experimental conditions. At maximum cut rates, performance of 7500-cpm probes was similar to that of 5000-cpm probes, suggesting that 7500-cpm probes may be used without sacrifice of flow rate and IOP stability.

TRANSLATIONAL RELEVANCE

Customization of vitrectomy parameters allows greater surgeon control during vitrectomy and may expand the usefulness of vitrectomy probes.

[Optimizing the financial impact of transitioning to transconjunctival vitrectomy and microincisional phacoemulsification]

OBJECTIVES

To report the financial impact of using modern lens and vitreoretinal surgical techniques.

MATERIALS AND METHOD

Bottom-up sterilization and consumables costs for new surgical techniques (microincisional coaxial phacoemulsification and transconjunctival sutureless vitrectomy) and the corresponding former techniques (phacoemulsification with 3.2-mm incision and 20G vitrectomy) were determined. These costs were compared to each other and to the target costs of the Diagnosis Related Groups for public hospitals (Groupes Homogènes de Séjours [GHS]) concerned, extracted from the analytic accounting data of the French National Cost Study (Étude Nationale des Coûts [ENC]) for 2009 (target=sum of sterilization costs posted under medical logistics, consumables, implantable medical devices, and special pharmaceuticals posted as direct expenses).

RESULTS

For outpatient lens surgery with or without vitrectomy (GHS code: 02C05J): the ENC's target cost for 2009 was 339€ out of a total of 1432€. The cost detailed in this study was 4 % higher than the target cost when the procedure was performed using the former technique (3.2mm sutured incision) and 12 % lower when the procedure was performed using the new technique (1.8mm sutureless) after removing now unnecessary consumables and optimization of the technique. For level I retinal detachment surgeries (GHS code: 02C021): the ENC's 2009 target cost was 641€ out of a total of 3091€. The cost specified in this study was 1 % lower than the target cost when the procedure was done using the former technique (20-G vitrectomy) and 16 % less when the procedure was performed using the new technique (transconjunctival vitrectomy) after removal of now unnecessary consumables and optimization of the technique.

DISCUSSION AND CONCLUSIONS

Contrary to generally accepted ideas, implementing modern techniques in ocular surgery can result in direct cost and sterilization savings when the operator takes advantage of the possibilities these techniques offer in terms of simplification of the procedures to do away with consumables that are no longer necessary.

Safety of 20-gauge transconjunctival sutureless vitrectomy

PURPOSE

To study the safety of 20-gauge transconjunctival sutureless vitrectomy.

METHODS

Clinical data of patients who underwent 20-gauge transconjunctival sutureless vitrectomy for the first time, for various disorders, were reviewed retrospectively. The main outcome measures were the number of sclerotomies requiring suturing as well as the intra- and postoperative complications.

RESULTS

A total of 179 operations were performed. Indications for vitrectomy included 68 idiopathic epiretinal membranes, 26 macular holes, 23 phakic and 16 pseudophakic retinal detachments, and 46 various other, less common etiologies. Of these 179 operations, 166 (93%) were sutureless. Of the 537 sclerotomies created, 25 (5%) received a single transconjunctival-scleral suture. Intraoperative complications included premature dislodging of the cannulas in 2 sclerotomies and an iatrogenic horseshoe tear at 1 sclerotomy site. Postoperative complications comprised transient hypotony in 14 cases, subconjunctival gas in 2 cases, and choroidal effusion in 1 case. No serious complications (such as endophthalmitis) were observed.

CONCLUSION

20-gauge transconjunctival sutureless vitrectomy can be considered safe, as the intra- and postoperative complications observed are neither numerous nor significant. Sclerotomies appear to be safe and relatively easy to perform, without compromising the advantages of sutureless surgery.

Comparison of 23-gauge sutureless sclerotomy architecture and clinical outcomes in macular and non-macular surgery using spectral-domain optical coherence tomography

PURPOSE

To compare the 23-gauge (23-G) sutureless vitrectomy incision architecture in macular and non-macular surgery, using anterior segment spectral-domain optical coherence tomography (SD-OCT), and to evaluated its influence on clinical outcomes.

METHODS

A prospective, observational case series of 43 patients who underwent primary transconjunctival 23-G pars plana vitrectomy (PPV) for macular and non-macular diseases. All sclerotomy wounds were imaged 1 day after surgery using the anterior segment module of SD-OCT (OCT Spectralis; Heidelberg Engineering, Heidelberg, Germany). Sclerotomy architecture, including good wound apposition, presence of gaping and misalignment of the roof and floor of the incisions were evaluated. Preoperative, intraoperative and postoperative medical record data were also prospectively collected.

RESULTS

  Incision gaping and misalignment of the roof and floor occurred more frequently in the superotemporal and superonasal quadrants than in the inferotemporal quadrant (p < 0.05) and was more frequent in the non-macular group than in the macular group (p < 0.05). The incidence of incision gaping increased significantly as the incision angle increased. In the macular group, the mean postoperative intraocular pressure (IOP) did not change from the preoperative value, whereas in the non-macular group, the mean IOP decreased significantly from 15.09 ± 2.58 mmHg preoperatively to 12.18 ± 3.25 mmHg on the first postoperative day (p < 0.005). The mean IOP did not differ significantly between the two groups of surgery at 1 week, and at 1 month postoperatively.

CONCLUSIONS

  In 23-G PPV, non-macular surgery is associated with a significant postoperative IOP decrease in comparison with macular surgery, which could be explained by the most remodelled wound architecture.

[Sclerotomies analysis using Spectral Domain OCT in sutureless vitrectomies complicated by endophthalmitis]

INTRODUCTION

Transconjunctival sutureless vitrectomy is a recent advance in vitreoretinal surgery. Some authors have reported an increased risk of postoperative hypotony and endophthalmitis and recommend the creation of oblique incisions, intended to be self-sealing, so as to reduce these risks. However, there is still a debate about the best architecture for transconjunctival sutureless incisions.

MATERIALS AND METHODS

We report two cases of acute endophthalmitis occurring after 23 and 25 gauge transconjunctival sutureless vitrectomy. We analyzed the scleral incisions using the anterior segment module of the Spectralis(®) OCT. To our knowledge, this is the first direct description of the appearance of sclerotomies associated with endophthalmitis.

RESULTS

The anterior segment module of Spectralis(®) OCT permitted a high-resolution evaluation of the architecture of the scleral incisions. We found straight, gaping incisions with misaligned edges and vitreous incarceration.

DISCUSSION

By way of these two case reports and a review of the literature, we discuss the contribution of anterior segment OCT in the analysis of scleral incision architecture in sutureless vitrectomy. Our findings are consistent with those reported in the literature. The presence of a direct incision, wound gap or edge misalignment are associated with an increased risk of early leakage and postoperative hypotony.

CONCLUSIONS

The anterior segment module of the Spectralis(®) OCT is a valuable tool for non-invasive, painless and high-resolution documentation of sutureless vitrectomy incisions. It allows for causal analysis and better understanding of the conditions associated with endophthalmitis after sutureless vitrectomy.

Influence of sutureless 23-gauge sclerotomy architecture on postoperative intraocular pressure decrease: results of a multivariate analysis

PURPOSE

To evaluate the factors affecting the postoperative intraocular pressure (IOP) decrease in 23-gauge (23-G) sutureless vitrectomy, including incision architecture evaluated by anterior segment spectral-domain optical coherence tomography (SD-OCT).

METHODS

A prospective cohort study of 43 patients who underwent primary transconjunctival 23-G pars plana vitrectomy. All sclerotomy wounds were imaged 1 day after surgery using the anterior segment module of SD-OCT (OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany). 23-G sclerotomy architecture, preoperative and postoperative medical data were also prospectively collected.

RESULTS

Multivariate logistic regression analysis, with backward elimination, found that surgery duration (adjusted OR = 9.17, p = 0.020) and loss of wound apposition (adjusted OR = 15.12, p = 0.022) were risk factors for significant postoperative IOP decrease (≥3 mmHg) 1 day after surgery; while age, gender, myopia, and gas tamponade were not risk or protective factors for postoperative IOP decrease.

CONCLUSIONS

In 23-G pars plana vitrectomy, the early postoperative decrease in IOP is mainly influenced by surgery duration and the self-sealing nature of the sclerotomy. The IOP decrease was not influenced by the presence or the absence of gas tamponade.

Outcomes of 23-gauge pars plana vitrectomy in vitreoretinal diseases

Purpose

The aim of this study was to assess the efficiency and reliability of the 23-gauge (23G) transconjunctival vitrectomy system and examine possible complications of this surgical technique in a variety of vitreoretinal conditions along with early postoperative intraocular pressure (IOP) changes.

Materials and methods

A total of 350 eyes of 324 patients having undergone 23G transconjunctival vitrectomy were included in this prospective study. A total of 150 (46.2%) were male and 174 (53.8%) female, with a mean age of 61.28 ± 15.67 years. Mean follow-up time was 8.3 months.

Results

Mean BCVA logMARs were as follows: preoperatively 0.839 ± 0.59, postoperatively first day 2.07 ± 0.76, first week 1.14 ± 0,43, first month 0.63 ± 0.26 and last examination 0.359 ± 0.17. Mean BCVA decreased significantly (P < 0.001, P < 0.028, respectively) on postoperative first day and first week, mainly due to air or gas tamponade, and increased significantly in the first month and final control in almost all indications (P < 0.001). Postoperative mild hypotony (IOP ≤ 10 mmHg) was detected in 112 (32%) eyes on day 1 and in 59 (16.8%) eyes in week 1. While postoperative serious hypotony (≤5 mmHg) was detected in 34 (9.7%) eyes on day 1, it was not detected in any eyes at the end of the first week. None of the eyes required an additional gas tamponade or any other procedure in the early postoperative period due to hypotony. A total of 13 (3.7%) eyes were reoperated for recurrent vitreous hemorrhage; 23 (6.5%) eyes were reoperated on a second time, nine (2.5%) a third time, and 1 (0.2%) a fourth time for recurrent rhegmatogenous retinal detachment. Postoperative fibrinoid reaction was seen in 17 (4.8%) eyes on the first day and responded well to the medications. Cataract development was found in 61 (22.5%) of the 270 phakic eyes after a mean duration of 6.4 ± 3.5 months. Anatomical success was obtained in 86% of the patients and functional success in 72%.

Conclusion

The 23G transconjunctival vitrectomy system is safe and effective in a wide field of vitreoretinal conditions. It is a good alternative to 20G and 25G techniques but needs some improvement mainly in regards to the instruments and related techniques; further larger controlled group studies are needed.

[Sutureless transconjunctival 20-gauge vitrectomy]

PURPOSE

To evaluate the safety and efficacy of 20-gauge transconjunctival sutureless vitrectomy for a variety of vitreoretinal conditions.

PATIENTS AND METHODS

This study was a retrospective clinical case series examining 29 eyes of 29 patients treated with 20-gauge transconjunctival sutureless vitrectomy. The main outcome measures included intraocular pressure, visual acuity, surgical time, and intraoperative and postoperative complications.

RESULTS

The mean follow-up duration was 5.7 months. There were only two cases of postoperative ocular hypotony (6.9%) and one suspect case of endophthalmitis. Mean overall acuity improved from 0.495 logMar at baseline to 0.29 logMar (p=0.002) and mean total operative time was 19 min. We observed no cases of retinal detachment.

CONCLUSION

Twenty-gauge transconjunctival sutureless vitrectomy is an effective surgical technique, but other studies are needed to confirm its safety and its value in other indications.

23-gauge transconjunctival sutureless vitrectomy: visual outcomes and complications

PURPOSE

To report results and complications of 23-gauge transconjunctival sutureless pars plana vitrectomy for a variety of vitreoretinal diseases.

METHODS

A prospective consecutive case series study was performed in 66 eyes of 66 patients. Indications for surgery were epiretinal membrane (n = 20), rhegmatogenous retinal detachment (n = 19: 14 pseudophakic, 5 phakic), macular hole (n = 16), vitreous hemorrhage (n = 5), cyclodialysis (n = 1), intraocular lens luxation (n = 1), asteroid hyalosis (n = 1), congenital retinoschisis (n = 1), and endophtalmitis (n = 2). Main outcome measures included visual acuity, intraocular pressure, and intra- and post-operative complications.

RESULTS

Mean patient age at time of operation was 68 ± 12 years. Overall, visual acuity improved from 1.03 ± 1.00 logMAR preoperatively to 0.32 ± 0.33 logMAR postoperatively (p < 0.01) after a mean follow-up time of 9.3 ± 4.7 months. Mean preoperative intraocular pressure was 13.9 ± 3.5 mmHg, and mean postoperative intraocular pressure was 17.9 ± 9.6 mmHg on day 1 (p < 0.01) and 14.7 ± 2.8 mmHg (p = 0.05) at final visit. Concerning complications, 2 cases of hypotony and 7 of hypertony occurred on day 1, a macular hole reopened some weeks later, and a retinal detachment recurred in one case.

CONCLUSION

23-gauge transconjunctival sutureless vitrectomy is an effective and safe technique for a variety of vitreoretinal diseases.

Advantages and limitations of small gauge vitrectomy

Small gauge vitrectomy utilizing 23- and 25-gauge instrumentation has definite advantages, but also limitations, due to the physics of smaller instruments and sutureless surgery. Higher infusion and aspiration pressures are needed to remove the vitreous using 23- and 25-gauge probes. The advantages include decreased surgical times, less tissue manipulation, reduced inflammation and pain postoperatively with more rapid visual recovery. A disadvantage is greater instrument flexion than 20-gauge probes, making small gauge vitrectomy more appropriate for indications such as vitreous opacities, epiretinal membranes, macular holes, and simple retinal detachments. There are also some increased complications related to small gauge vitrectomy, including dislocation of cannulas intraoperatively, early postoperative hypotony, choroidal detachment, and possibly an increased risk of infectious endophthalmitis.

Intraoperative mechanical failure of a 25-gauge vitreous cutter

PURPOSE

To describe the mechanical failure of a 25-gauge vitreous cutter intraoperatively and the management of this complication.

METHODS

An observational case report of a 39-year-old Type 1 diabetic woman with proliferative retinopathy who underwent pars plana vitrectomy with 25-gauge instrumentation.

RESULTS

Breakage of the 25-gauge vitreous cutter occurred during delamination of a dense fibrovascular plaque. The cutter was successfully removed via the trocar as a single unit. The patient recovered with no sequelae.

CONCLUSIONS

Breakage of 25-gauge instrumentation intraoperatively is a very rare event. This case constitutes only the second reported complication as such. However, it is easily managed and can result in few, if any, adverse sequelae.

Differences between the combination of the 25-gauge vitrectomy with phacoemulsification versus 20-gauge vitrectomy and phacofragmentation

Introduction:

In the present study we determine the differences observed between 25-gauge-vitrectomy combined with phacoemulsification, and the 20-gauge-vitrectomy combined with pars plana phacofragmentation.

Methods:

A prospective study of a sample of 987 eyes of 661 patients randomly divided into two groups. 25-gauge-vitrectomy plus phacoemulsification included 486 eyes, and 20-gauge-vitrectomy plus phacofragmentation 501 eyes. We evaluated the differences at the time of the surgery, the intra-and postoperative complications, and the variations in intraocular pressure.

Results:

The final visual outcome was similar in both groups. The most important differences between groups were: surgical time was faster in group 1 than in group 2, (mean time: 35.16 ± 3.49, 44.74 ± 5.30 minutes). Intraoperative complications were more numerous in group 1. In group 1, postoperative low levels of intraocular pressure are present in all patients with 2.77% of patients with hypotension (<8 mmHg), and three choroidal effusion. In group 2, intraocular lens decentration and retinal detachment are more frequent (2.38% and 1.39%, respectively).

Conclusions:

In the present study, both techniques have a similar number of complications and have a similar postoperative outcome, and are valid for the management of the pathologies selected.

[25-Gauge transconjunctival vitrectomy in a case of bilateral epiretinal membrane associated with a Terson syndrome]

The formation of epiretinal membranes associated with proliferative vitreoretinopathy is known to be a complication of Terson syndrome. We report the first case of a 25-Gauge transconjunctival sutureless vitrectomy performed in one eye as treatment for an epiretinal membrane secondary to a case of Terson syndrome (most probably due to a history of subdural hematoma in childhood). Following a review of the current literature on the subject we report the physiopathologic mechanisms of Terson syndrome and the explanation for the proliferative vitreoretinopathy formation.

[Outcomes of 110 consecutive 25-gauge transconjunctival sutureless pars plana vitrectomies]

PURPOSE

To evaluate the safety and efficacy of the 25-gauge transconjunctival vitrectomy system for a variety of vitreoretinal surgery indications at short-term follow-up.

METHODS

Retrospective study of consecutive interventional cases that underwent surgery performed by one surgeon using the Alcon 25-Gauge vitrectomy system, in Bordeaux University Hospital, from September 2004 to May 2006. Indications were epiretinal macular membrane (72 eyes), macular hole (24 eyes), and other diseases (14 eyes).

RESULTS

One hundred and ten eyes of 105 consecutive patients underwent surgery. None required conversion to 20-gauge vitrectomy or wound suture. One iatrogenic retinal break occurred intraoperatively. Two transient wound leaks, seven cases of hypotonia, one of chronic endophthalmitis, one of rhegmatogenous retinal detachment, one of retinal break, two recurrent intravitreal hemorrhages, and six cases of hypertonia were noted postoperatively. Three eyes required additional surgery. Mean overall visual acuity improved from 0.691 +/- 0.465 logMAR preoperatively to 0.476 +/- 0.492 logMAR at 1 month (p<0.0001). Visual acuity improvement was statistically significant for eyes with macular epiretinal membrane (p<0.0001) and macular hole (p=0.0158). The macular hole closure rate was 87.5%. Mean operative time was 25.91+/-10.94 min. Mean follow-up was 13.32+/-18.1 weeks. Thirteen eyes developed cataracts during the follow-up period.

CONCLUSION

Vitrectomy with the 25-Gauge system appears to be relatively safe and particularly appropriate for macular surgery.